A number of spectrometers are known for selectively detecting light of various wavelengths. In particular, spectrometers are known for detecting individual or narrow wavelength bands of light, including wavelengths in the ultraviolet, visible, or infrared bands. In some cases, an optical filter is used in conjunction with a wide spectrum detector. The optical filter typically selects a particular wavelength of light for detection by the detector.
In many cases, the optical filters are formed from thin films that reflect or transmit a narrow band of wavelengths. Such filters are often constructed from several hundred layers of stacked narrow band filters, which collectively reflect or transmit a narrow band of wavelengths. Arrayed waveguide gratings are also commonly used. A limitation of many of these optical filter/detector combinations is that they often can only detect a single wavelength or a very narrow band of wavelengths dictated by the selectively of the optical filter. This can make it cumbersome to detect and/or monitor the spectral emission of light across a range of wavelengths and/or range of wavelength bands because numerous optical filters/detectors may be required, with each only detecting or monitoring a single or very narrow band of wavelengths.